Users on Flickr's recently-launched sites for Germany, Korea and Singapore were met with unlockable content filters that have spawned a user revolt in Germany, reports Epicenter, a Wired blog.

The new language sites prevent access to content flagged "Moderate" or "Restricted," even to consenting adults. Further, Flickr did not communicate news about the filters to its users in any way.

Once the restrictions were discovers, German users began uploading thousands of anti-Flickr images to the site, often tagged thinkflickrthink.

On Wednesday of last week, Flickr responded to the German rebellion, stating the restrictions were in place because of stringent age verification laws in Germany.